


Warm Fire

by VenomQuill



Series: Alliancetale [3]
Category: Undertale (Video Game)
Genre: Alliancetale, Boss Fight!, Gen, He's a sweet goatbro, I'm struggling to make Asriel use his attacks, Snowdin (Undertale), even though he's in his early twenties here lol
Language: English
Status: Completed
Published: 2019-10-11
Updated: 2019-10-11
Packaged: 2020-11-28 00:10:37
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,601
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20957225
Author URL: https://archiveofourown.org/users/VenomQuill/pseuds/VenomQuill
Summary: Undyne has trekked all the way through Snowdin, completing puzzles and sparring with the teens in the forest. Now she faces against Asriel, Prince of All Monsters, a powerful being with a sharp mind who blocks her way to Waterfall.





	Warm Fire

**Author's Note:**

> Find it on dA: http://fav.me/ddi1dtx

Undyne’s boots crunched through the snow, the stark red boots accented gold sharp against the white. The wind picked up farther down the trail. Undyne’s sharp yellow eyes studied the trail flanked by snowy evergreens. The sloshing of the river burdened by ice cubes flowed to her left.

The fluttering snowflakes got denser and denser until Undyne could hardly see the tip of her nose. She clenched her jagged teeth and started to shiver. The bandana wrapped around her forehead did nothing for her bare forearms, or even the rest of her arms and chest donned with a thin shirt.

She stopped upon hearing a light, masculine voice. “Hello, Surfacer!” Excitement laced the voice like heavy icing. That fuzzy monster’s excitement had no end, did it? “Allow me to introduce you to some complex customs of the Underground. What with being a monster and all, I’m sure you’ll fit ri–” The voice stopped.

…

“No… no that’s not how this is going to work. You’re a surfacer. It’s my job to capture you and bring you back to Mo–Queen Toriel! B-before, uh, the Captain does! Ready yourself for the fight of a lifetime!”

The wind stopped and the snow fell away. Undyne looked around. The snowy wind swirled around a giant, invisible bubble that surrounded them. Standing mere feet away was the Prince of Monsters. His blue-violet and white clothes fluttered in the slight wind, and the colorful scarf around his neck fluttered behind him, as he kept it tied backwards like two very thin, long capes. Two shorn, curled horns separated the short blonde hair on his head.

_“ASRIEL BLOCKS THE WAY!”_ exclaimed the equally as excited voice of her spirit aid.

Undyne glanced at the tall skeleton, invisible to all but her. _“OH-OH! RIGHT!”_ He cleared his non-existent throat. _“PRINCE ASRIEL 60 ATTACK, 60 DEFENSE. HE’S HIS FATHER’S SON, THE PRETTY COOL OLDER BROTHER!”_

Undyne raised an eyebrow. What did he mean by–?

“Yep! Asgore’s my dad, if you didn’t know, and Queen Toriel’s my Mom. I’m sure you guys will get along really well.” Though, as he said that, Asriel’s grin wavered a little. Balls of emerald fire centered by white swirled around her in a very familiar DNA pattern. Undyne hopped and scooted forward and back to keep from getting burned. Though, the wave of heat was welcoming.

Undyne summoned her trusty spear and held it in a tight grip in both hands. “You missed me! Got any better attacks?”

Asriel chuckled. “Challenging, huh…? Welp! I’ve never backed down from one of those before!”

_Oh no._

Asriel waved his hands in grand gestures, throwing waves of searing fireballs at Undyne.

Undyne blocked one ball of fire with her spear. She spat as another burned her shoulder. She ran out of the way of any further attacks, thankfully. Undyne puffed and, once the attack ended, looked at her shoulder. _HP 25/20._ She turned back to the sentry. “I won’t fight you,” she relented. If Asriel _was_ his father’s son, she could face a very long and bitter fight.

“You won’t fight me?” Asriel raised an eyebrow and then shrugged. “Well, then. Can you face my _orange attack?_”

He sent more balls of fire at her, these ones orange with no light center rather than green with a white puff of flame. Undyne slipped through most of them with ease, still a little weirded out as she couldn’t feel them pass straight through her.

Then, her silver SOUL flashed orange.

Undyne yelped as a sudden pain stabbed through her. She moved and the pain was gone. A large ball of emerald fire rushed at her. Distracted by this new phenomenon, it crashed straight into her SOUL.

“Hah! You’re orange now!” Asriel crowed with a triumphant smirk.

Undyne blinked stupidly, watching her SOUL shiver before her. Right now, while no bullets were in the air, she could feel no pain of standing still. That didn’t mean it wasn’t _weird._

Undyne took a deep breath and held her spear up as a shield again.

“Watch this!” Asriel waved his hands, each motion bringing forth a wave of fire. Though most waves were green, a few were orange. Undyne struggled to stay moving _and_ dodge these fiercely moving attacks. Her spear blocked a ball of green fire, but another hit her in the side and she stopped, stunned, for a moment before the pain of standing still set in and she continued to move._ HP 9/20._

Undyne, puffing, held out her spear in a shield. Asriel looked her over. “Are… are you sure your okay? I’m not being too hard on you, am I?”

Undyne snorted. “No way! Give me your best shot, punk!”

The boss monster blinked and then grinned. “Okay! Well, can you handle _this_?” He cackled and sent another attack at her, this one a series of circles getting larger and more spread out the farther from Asriel they got. Undyne dodged most of the attacks, batting one away with her spear and running straight into another.

The attack ended. Asriel looked her over nervously. He started to speak, as if to prompt her health, but stopped himself. He stood up straight. “If you keep going like this, I may have to use my _special attack!_”

Undyne perked up. Special attack?

Asriel snapped his fingers. Undyne’s SOUL turned silver. She took a deep breath and nodded. Asriel waved his hands. However, a few balls of flame were a lighter shade of green without the white flame centers. Undyne ran into one. Some of the pain from the burn in her shoulder faded a little. Undyne side-stepped a few attacks, dissipated another with her spear, and ran into a second lighter green ball of fire.

Undyne stood up straight. Asriel announced, “And if you think my orange attack is cool, check _this_ out!” Asriel snapped his fingers. Her silver SOUL turned deep blue. Undyne’s SOUL hit the ground and she staggered, gasping as the gravity of Earth increased dramatically. She looked up. Asriel held out one hand. A long, white sword appeared in his hand. With a slight curl, a half-moon chunk was sliced out of the other end while a hole with two bars for support was punched out of the blade near the hilt, which curled and branched like gold and white vines. When he whipped it toward her, a faint rainbow shine gleamed off its blade and followed it as it moved.

Undyne moved out of the way, just barely missing the tip of his sword. He shoved his empty hand at her, sending a swirl of cyan fire at her. Undyne started to move but forced herself to keep still. The fire passed right through her.

“The future _God of Hyperdeath!_” He summoned a second sword and held them up high. Papyrus helpfully pointed to her side. “Here! There!” A second after he pointed to her left, Asriel swung his sword down. Undyne hopped from side to side. Her spear parried his right blade, but his left blade cut into her side.

“A future Royal Guard!” He let go of one sword and threw another few swipes of cyan fire and others of orange fire at her. Undyne moved and stayed still whenever necessary.

“The Future of Humans and Monsters!” Asriel blinked. “Well, Chara took that spot. But they said that since I’m their brother, and a monster, I’m part of that, too.” Asriel snapped his fingers. Chara’s SOUL changed from blue to orange. Undyne sucked in her breath. When staying still causing pain to stab through her SOUL, and moved. Another few strings of emerald fire like a DNA string flowed toward her. Undyne managed to parry two and barely miss one. Near the end, however, a puff of lighter green fire swirled around her. Undyne waved her hand through it. The cut on her waist healed quite a bit–not completely, but well enough.

Asriel’s attack ended. Undyne took out a bunny shaped cinnamon roll. The pain and lingering burns and cuts from her wounds vanished in an instant.

“Frisk talks so much about capturing a surfacer, I can’t wait to see the look on their face when _I_ get to capture you!” Asriel laughed, though Undyne didn’t feel any actual maliciousness in it. Instead, he laughed like he was telling a joke. Was this battle just that to him? Or did he not like hurting her…?

Asriel held up a hand. Rings of fire burst out from in front of Asriel. Undyne hopped and ducked and moved as best she could. Though the air near her warmed, not a single ball of fire hurt her. Once the attack ended, Undyne took a deep breath and summoned her spear.

“Mom will _finally_ stop treating me like a baby! Probably.” Asriel snapped his fingers. Undyne’s should changed from orange to silver. Another DNA ring swirled around her. Undyne blocked one with a spear. Another hit her lower chest, causing her to wheeze and step back.

“Then my sibling… I don’t think they’ll change much,” Asriel admitted. He summoned a sword and swiped it at her. Undyne danced out of the way. After a few slashes, he sent a stream of cyan fire at her. She stood stock still. Although she couldn’t feel the bullets phasing through her, their warmth coursed through her whole body.

“I’ll finally get the respect I deserve! But…” Asriel’s eyebrows wrinkled and he looked away. “Would it really be worth it…?”

Undyne held out her spear in front of her. Rings of fire burst and swirled toward her. A fireball hit her spear while another crashed into her shoulder.

“Someone like you is really great! And… I don’t know if they’ll let you go…” He held out his other hand and summoned another sword. He swiped both swords at her, forcing her to dance from side to side. He slapped them together at the end, causing a few white sparks to flutter away. Undyne batted one away with her spear and side-stepped the others.

“After I capture you and send you away…” Asriel frowned. This attack, another strand of DNA flames, had orange flames to the left and blue to the right. Undyne ran straight into two fireballs–one orange and one blue. Although her spear blocked the orange one she stopped in, the blue one hit her moving SOUL.

Asriel shook his head and set his gaze. “Whatever! Just give up!” He snapped his fingers. Undyne’s SOUL turned orange. He sent waves of orange and emerald fire at her. She caught a few light green ones that mingled with the orange.

Asriel forced a smile. “Give up for face my _Special Attack!_”

Undyne perked up. Yes! A special attack! …could she handle one of those? Oh, what was she thinking? She was Undyne! She could handle anything!

Asriel sent another burst of fire rings at Undyne. She swatted two away with her spear and dodged the rest.

“Yeah!” Asriel chuckled, his smile relaxing a little. “I’ll use that special attack really soon!” He snapped his fingers. Her SOUL turned from orange to blue and gravity increased on her. Asriel waved his hands, sending a few sweeps of fire, some of which were blue, at her. Undyne grimaced as a blue one rammed into her chest.

“I’m warning you: Your last chance before I unleash my _special attack!_” He sent another few rings of fire at Undyne, forcing her to hop from side to side to avoid getting burned. A couple were light green, but she missed those ones.

Asriel, a very slight pant in his voice, straightened up. “Alright! Well, I promised to show you my special attack. So…!” He waved his hand with a triumphant grin. A dog stood between them, blinking up at Asriel with wide, innocent eyes and wagging his tail. In his mouth was a large star-shaped attack. Oh, man. That would have been _awesome!_ Asriel gasped, “What?! Wait! No, dog! Let go of that!” The dog blinked and started to walk off. Asriel started toward him. “No, no! Come back! I’ll give you a pat on the head–!” The dog hesitated. “–if you return my _special attack!_” The dog let out a muffled bark and ran away. Asriel puffed and stepped back into place. “Aw. Darn dog. I guess I’ll just use a super cool regular attack.”

Undyne watched the dog go before summoning her spear again. Although she was itching to use her spear volley, she had an idea that Asriel might take that as a further challenge… and that Chara would dislike her even more…

Asriel sighed, “Sorry I sort of hyped up my special attack and didn’t use it. So have a really cool regular attack!”

Asriel summoned his sword and snapped his fingers. Undyne’s SOUL turned orange. Undyne moved out of the way of his sword, and then dipped through the rings of fire. She blocked one, and barely dodged a second. Ooh no, she was going to get beaten, wasn’t she? No! She was determined to win!

Her SOUL turned blue. His fire swirled around her, some orange and some blue. A few seconds later, her SOUL turned silver and the fire balls returned to their natural green with white centers. The attack tapered off until only a few bullets were left drifting around her.

Asriel set his hands on his knees. _Huff!_ “Well!” _Puff!_ “That was–” _puff, _“–interesting!” _Huff!_ “You really are a worthy opponent.” He stood up straight. “So, I’ll be glad to spare you, Surfacer. Please, accept my mercy!”

Undyne puffed. She held out her spear and dropped it. It clanged to the ground before dissipating. She nodded. “Y… yeah. Mercy.”

Asriel grinned. He relaxed out of his fighting position and laughed. “Great! Amazing duel on your part, Surfacer!” He chuckled upon seeing her annoyed expression. “Oh, I know your name’s not _‘surfacer,’_ Undyne.” His grin faded and he turned away. “But I failed to capture you and now I’ll never get any respect as long as I’m still a _sentry._”

Undyne looked him over. She glanced to her side, where Papyrus was buzzing so hard that his bones silently rattled. She sighed and bowed her head. “You’re a worthy opponent, Asriel. I think you’re… great. You don’t need to prove anything.”

Asriel grinned. “Really? Yeah! I knew you surfacers weren’t all bad! You’re tough. You’ll survive. And I’ll survive being babied by my mother, I guess. Heh. So, I, Prince Asriel Dreemurr, hereby grant you permission to leave Snowdin! If you want to get to the castle, just keep heading east through Waterfall. You’ll hit Hotland, and then pass through to the CORE, which will lead you straight to New Home! That’s where Mom lives! If you go to her yourself, I’m sure you can work out a way for you to stay here! After all, we’re trying to open the Barrier with SOUL power, and monster SOULS are too weak. In fact, I’m sure if you ask nicely, Mom will bake a pie!” Asriel hesitated. “Uh… could you do that for me when you get there? Hehe!”

Undyne laughed. Well, pie did sound a little good. But what about _spaghetti?_ Nothing beat homemade spaghetti!

“Anyway,” Asriel went on. “I’ll be at home. If you want to, I dunno, hang out or something, I’ll be there!” He grinned and ran back in the direction of Snowdin. Without Asriel’s magic to keep the snow at bay, the snowstorm resumed and Undyne’s warmth and sight was robbed of her. She pushed her way back into Snowdin.

**Author's Note:**

> ,Azzy! <3
> 
> In battle, once Undyne gets to 9 HP or less, Asriel will comment on how rough he's being. When Undyne gets to 4 or less HP for the first time, he'll produce healing bullets. After that, there's a random chance every turn where Undyne has 4 or less HP for him to create healing bullets. Once Undyne gets to a certain HP, he'll stop fighting. But like Toriel, he doesn't have perfect control and can (rarely) [kill Undyne.](http://i.imgur.com/WWC20wC.jpg) In the instance that Undyne gets to 1 HP, she's considered too weak to fight back and will be captured! Asriels attacks do 5 damage while Undyne wears the bandana, making him one of the strongest enemies in the game. To make up for such foolishness, he occasionally heals Undyne with green bullets.
> 
> Orange SOUL means you can't stop moving or you will get hurt. Almost like standing still through an orange attack without invincibility frames. Blue SOUL acts just like in Undertale. Asriel has blue, orange, and green attacks. On the bullet board, his regular fire is white. In the story, it's green like the Soul of Kindness. Toriel's is crystal blue like the Soul of Patience, and Asgore's fire is yellow like the Soul of Justice. Blue + Yellow = Green, which was literally just a coincidence when I first made this SOUL-colored fire pattern all way back in "Fallen Under." (If Chara and Frisk had fire magic, they would both have red fire)
> 
> His bullet patterns are a mix between Asgore's and Toriel's with his own flare. The bullets are smaller, like Toriel. But he has colored magic like Asgore. He has a total of 6 unique attacks: [DNA Fire](https://www.wikihow.com/images/thumb/9/97/Beat-Toriel-in-Undertale-Step-1.jpg/aid8335033-v4-728px-Beat-Toriel-in-Undertale-Step-1.jpg), [Fire Wave](https://steamuserimages-a.akamaihd.net/ugc/496903330877775858/2A2C9D2EDA493EDF88F2B92C7703B93E30337F72/), [Fire Swip](https://i.ytimg.com/vi/bmQOJmRhug0/maxresdefault.jpg), [Fire Burst](https://lparchive.org/Undertale/Update%2030/14-2686.png), [Chaos Saber](https://lparchive.org/Undertale/Update%2037/19-3131.png), and Blade Slice, which is Chaos Saber but with one sword that takes half the bullet box, while the other half is a less complicated, one-sided [Fire Wave. If you want to get technical, he has seven with his seventh being a special attack consisting of ](https://steamuserimages-a.akamaihd.net/ugc/496903330877775858/2A2C9D2EDA493EDF88F2B92C7703B93E30337F72/)["Star Blazing"](https://lparchive.org/Undertale/Update%2037/24-3135.png) and ["Shocker Breaker"](http://nosimpleway.brontoforum.us/letsplay/ut/lput1035.png) as well as some fire attacks in a complex pattern. Just for you Disbelief!Asriel or "Last Man Standing" Asriel fighters. Haha The attacks are weaker/slower and more spread out, and some fire bullets are green, because: A. He's not a god, and B. He doesn't want to kill you. But this attack is by far the easiest attack to accidentally kill you.
> 
> Also: If you FIGHT rather than SPARE, it's a one-hit kill. He'll say "You... you really do hate me..." before collapsing and saying "They were right. Surfacers don't like mercy, do they...?" Then he'll dust.


End file.
